In this chapter, we looked into the technology behind cryptocurrencies such as Bitcoin and Ethereum. This technology enables the decentralization of storing values or code. We also covered cryptography by using private and public keys to secure the integrity of any data. Further on, we learned about hash functions, proof of work, consensus, and the basic concepts of blockchain programming.
In the next chapter, we will learn about a smart contract, a kind of program that lives in Ethereum. A smart contract is different than a kind of program that lives in a server, such as an application written with Ruby on Rails, Laravel, or Django. The differences are more than just the syntax; the concept is radically different than a normal web application.